Push-off device



July 10, 1945. W. ST'RAIUSS PUSH-OFF DEVICE Filed 001:. 9, 1942 2 Sheets-Sheet 1 m m M BY SfTaLLsS ATTORNEY July 10, 1945. w. STRAUSS PUSH-OFF DEVICE Filed Oct. 9, 1942 2 $heetsSheet 2 N NW NW mN QM 9W *QN m Nm i 1 Wm amvm 9 m k AK Wm Um INVENTOR.

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ATTQ RNEY Patented July 10, 1945 UNITED sTArEs PATENT OFFICE.

"PUSHrOFE' DEVICE William Strauss, *Philadelph-ia, Pa, assignor' to Ji JStOkGS} Machine Company, a corporation of Pennsylvan a 7 Application October 9, 1942, Serial No. 461,483

iii-Claims.

This invention relates to avde'vice fordischargingmolded articles from a molding press. In particular, it relates to a device for discharging molded articles from a press by means of an air blast, and also embodies means'forvpositiv'ely removing the article from the press where the air blast alone isineffective for this. purpose.

In Unitedl States Patent 2,242,189 there is shown the use of afixed air jet fordischarging molded articles from a press by an air blast, and a pivoted knock-01f lever.is-also provided to. positively discharge the article from'the press in case it is not removed by the air blast. My prese invention combines both functions in one device; that is, the air nozzle is arranged to traVeILbetween the molded parts in the path of the moldedarticle, and if the air jet is not effective in removing the article from the m'oldzparts, thenthe air nozzle engages the article vand dislodges it from the mold part.

My invention is illustrated in the accompanying drawings in which Figure 1 is a side elevational View of a part of a molding press showing my I push-off devi mounted in proper position, certain lowermold 25 parts being shown in section;

Figure 2 is a plan view of the push-off devic certain air nozzles being broken away to'show'the parts located beneath the nozzles; and

Figure 3 is a diagrammatic view of the control system for operating the push-off device.

Referring to the drawings, I indicates a lower cross-head of a molding press carr l lflheated platen 2 U which in turn carries the'lower'iiie plate 3. Any desired number "ofdie elements may-beembodied in the plate 3, and in the arrangement shown in Eigure 1, two die elements 3a'and 3b,

shown in section,'are arranged to form' the-upper surfaces of molded knob elements 41; and-4b; respectively. It is understood that"the knfobele-- ments areshown in inverted I OSiti'onimFigure 1.

The upper mold part 5 cooperating with "the lower die plate 3 is carried by an upper, heated platen 'B. It will" be understood that thepress embodies suitable means for producing relative Vertical movement betweeni platens 'Z 'and B -to bring the mold parts together iii-molding relation and then to separate the mold parts-to theposition shown in Figure 1, "The-press 'a'lso embodies suitable knock-out pins'laand' lb-forbjeqiting the molded articles .from'die elements 3m and 3b in the .usual manner. "I'heif pushwfij device is provided with a, mounting bracket 8' having a mounting stem 8a adjustably. clamped a mounting bracket 9 secured to the front face of cross head I. Such an arrangement permits vertical adjustment of the position of the push-01f device with respect to the mold parts. The push-off device has an air cylinder 10 mounted at the top of bracket 8 and the rear end of this cylinder is supplied with air under pressure through a connection Illa leading to a suitable source of compressed air. A reciprocating piston II is mounted Within cylinder Ii] and carries a manifold 12 at itsl forward end arranged transversely thereof. The manifold 12 may be formed integral with the piston I I or they may be formed of separate units joined together. The manifold I2 is hollow and is closed at its open end by a suitable plug I211.

Air, or other'fiuid under pressure is'supplied to the manifold from a suitable source through a connection no. A series of air nozzles I311, I31), I30, I3d, 13c and |3f are mounted on manifold I2 and faresupplied with compressed air from the manifold. These nozzles are arranged horizontally and are directed in line with a molded article when in theposition shown in Figure 1. For example, the nozzle l3a in Figure l 'is positioned in line with knobs 4a anddb. The remaining-nozzles would'be positioned in line with other pairs of .knjobs in a mold adapted to mold six pairs of KIL bbssimuIta e S Y- Apair ofjspring'supporting rods "Ma and 14b are. positioned on oppositesides; of cylinder I0;

passing through holes formed in lateral flanges lflb and I00 carried by the forward endof cylinder l0 and are secured to manifold l2. A pair of compression springs l5a and 152) are carried'by rods Ma and Nb, respectively, and normally urge the manifold 12 to the. left so that the piston H is normally retractedin the cylinder l0, suitable means such as the double-nut shown being provided .on the ends of rods Ma and 14b to maintain the springs on the rods.

A stop rod 15 is secured to bracket -8 belowt-he forward end of cylinder ii] and extendsforward Offthe cylinder and passes through a holeformed in a depending flange I20 on manifold 12. A short coiled spring Ilia is carried'by the rod [2 between the bracket 8 and the flange in order to cushion the rearward movementof the-manifold l2. A'similar coiled spring Hib is positioned at the other end of the rod [6 onthe opposite side i of flange I20 and normally cushions the-outward movement of the manifold l2, the spring [6b be-- ing retained on the red by suitable means such as thedouble-nut shown.

Piston l I- has a central bore I la extending from the rear end forward into manifold l2 but=sto pping short of the bore inthe manifold. A vertical bore [2d is formed in the upper part of manifold I2 communicating with the front end of the bore Ila, and this bore is threaded and is normally closed by an adjustable screw I2e. A small horizontal bore lZf is formed in manifold I2 extending from the front face thereof and connecting at the rear end to passage I201. The arrangement is such that by adjusting screw I2e the amount of air which passes through the bore I2f may be regulated.

A safety switch I! is mounted on bracket 8 in a position where flange I20 on manifold I2 operates the switch stem I'Ia when the manifold is in its retracted position. A connecting cord I'Ib connects the switch in a suitable control circuit, one of the examples of which is shown in Figure 3. The construction of switch I! will depend upon the type of control to be exercised by the switch, but in the arrangement illustrated in the drawings, the switch is normally spring biased to open position but is held in closed position by the manifold in its retracted position, and the switch is connected in the control circuit in a manner to prevent operation of the press except when the manifold is retracted.

When installing the push-off device, the device is adjusted vertically until the air nozzles are in line horizontally with the molded articles when they are resting upon the knock-out pins as shown in Figure l, and the nozzles can move freely into the space between the upper and lower die elements without interference with these elements or with the knock-out pins. Air is supplied to cylinder III and manifold I2 in timed relation with the operation of the press in such a manner that when the press operates to open position, the manifold is moved forward and simultaneously air is supplied to manifold I2 so that air jets impinge upon the molded articles and discharge the articles from the press. By controlling the admission of air to manifold'IZ so that the jets are effective during the entire upward movement of the knock-out pins, usually all of the molded articles will be discharged from the press as soon as the articles have been pushed out of the mold cavities by the knock-out pins. In case an article adheres to a knock-outpin so strongly that the air blast is ineffective to remove it, continued movement of the manifold'will result in contact of one of the air nozzles with the molded article adhering to the pin and will dislodge the article from the pin. The arrangement is such that the manifold travels far enough to dislodge any articles which may be sticking to the back row of pins, and then the air is cut off from cylinder ID, The manifold is then returned to its normal position by operation of biasing springs I5a and IE2), the rate of return movement being controlled by the adjustment of the air throttling screw I22 which controls the discharge of air stored in cylinder I0 through passage I2 The air supply to mani fold I2 may be continued until the manifold returns to its normal position, thus the air jets are continued during the backward stroke of the manifold and serve to clean both mold parts of any loose material which may remain thereon. On the forward stroke of the manifold the movement is arrested by spring I62), and the return movement is arrested by spring Ita.

Various control circuits arepossible, and one example is shown in Figure 3. Compressed air from a suitable supply line I8 may besupplied to cylinder I0 through an electromagnetic valve I8a and to manifold I2 through an electromagnetic effective.

valve I817. These two valves are controlled in timed relation with the operation of the press by means of a cycle controller I9 which controls the press operating motor 20 which is energized from a suitable supply circuit 2| The controller I9 may be of any suitable construction and may be operated by a controller motor 22 which may also be energized from circuit 2| through controller I9. The arrangement is such that the press is operated through a succession of cycles, and usually a timing device is embodied in the controller for the purpose of stopping the press in closed position for a predetermined curing time, An electromagnetically operated switch 23 is included in the circuit to motor 20 and is controlled by safety switch II so that the motor circuit is closed only when the manifold I2 is in its normal retracted position. As soon as the manifold moves away from its normal position, switch.23 is de-energized and motor 20 cannot be energized to operate the press. Switch 23 may be a normally closed, normally de-energized relay, and switch I! would then be of the type which is normally biased to closed osition but is held in open position by manifold I2.

By providing the throttled vent I2f for the air stored in cylinder In after valve IBa closes, it is possible to use a simple on-and-off valve at Illa. Also, this arrangement provides for the easy adjustment of the rate of return of manifold I2 to its normal position. Furthermore, the air escaping through vent passage I2 f is directed in the same direction as the air jets and will assist in discharging the molded articles and cleaning the mold parts. If desired, a 3-way valve may be used at We or at I8b for controlling cylinder I0 and manifold I2,

From the foregoing it will be seen that I have provided a device in which the molded articles are normally discharged from the press by the action of the air blasts on the molded articles,

but the jet pipes or nozzles are mounted for movement transversely of the press in order to positively dislodge the articles from the mold parts or knock-out pins in case the air jets are in- A separate jet pipe is provided for each row of molded articles, and the various jet pipes are arranged in line with the respective rows of articles.

My invention is not limited to the use of compressed air since other gases or fluids may be employed if desired.

What I claim is:

1. A push-off device for a molding press comprising, in combination, a jet pipe manifold, a plurality of jet pipes mounted on said manifold and positioned to direct a plurality of substantially parallel air streams transversely of the press and into the space between the mold parts in said press to discharge molded articles therefrom, and means for mounting said manifold for movement in the direction of said air streams whereby said jet pipes come into contact with any molded articles which are not discharged from the press by said streams.

2. A push-off device for a molding press comprising, in combination, a jet pipe positioned to direct an air stream between the mold parts of the press to discharge molded articles therefrom, an air cylinder provided with a piston, said jet pipe being mounted on the piston of said cylinder for movement along its axis into the space normally occupied by the molded article when the press is open, a common source of fluid under pressure, separate valves for controlling the supply of fluid from said source to said jet pipe and to said air cylinder, and means for operating said valves in timed relation so that the air stream is directed against the molded article before said jet pipe moves into position to engage said article.

3. A push-off device for a molding press comprising, in combination, an air cylinder having a piston therein mounted adjacent said press for movement transversely of the press, a jet pipe manifold carried by said piston, a plurality of jet pipes mounted on said manifold and arranged to direct a plurality of parallel air streams transversely of said press for discharging molded articles from between the separated mold parts, a

. connection from said air cylinder to a source of fluid under pressure including a valve controlling the admission of fluid to said cylinder, a vent passage formed in said manifold and having a connection to the irmer space of said air cylinder, said vent passage being positioned to direct an air stream parallel to the streams formed by said jet pipes, and means for adjusting the rate of flow through said vent passage.

4. A push-01f device comprising an air cylinder having a piston therein, a jet pipe manifold carried by said piston, a plurality of jet pipes carried by said manifold and arranged to produce a plurality of substantially parallel air streams, spring biasing means for normally retracting said piston in said cylinder, a vent passage formed in said manifold and having a connection to the inner space of said air cylinder, said vent passage being positioned to direct an air stream parallel I to the streams formed by said jet pipes, and

means for adjusting the rate of flow through said vent passage.

5. A push-off device comprising an air cylinder having a piston therein, a jet pipe manifold mounted upon said piston and arranged transversely thereof, a plurality of jet pipes carried by said manifold and arranged substantially parallel with each other and substantially parallel with said piston, a pair of flanges extending laterally from opposite sides of said cylinder, a pair of guide rods secured to said manifold and extending rearwardly through holes formed in said lateral flanges, and a compression spring carried by each guide rod and serving normally to main- 

